This invention relates to headers with electrical feed throughs therein and, more particularly, to such header and feed through assemblies as are useful in electronic components such as electrolytic capacitor housings.
In the electronics industry there are many uses for electrically insulating headers with metallic feed through terminals therein. Many of these uses relate to component housings which must supply mechanical protection and electrical isolation. The feed through terminal facilitates electrical connection to the device. One common example of such a header with feed through terminals is the plastic cap used on computer grade electrolytic capacitor cans.
In the past, such headers have generally been manufactured by one of two methods. According to the most common technique, a single molding step forms the header around the metal feed through terminals and imparts to the plastic header its overall shape. Thus, final assembly requires but one molding step. A disadvantage of this technique is that most of the material cost of the finished assembly is in the metal terminals. If the molded plastic header is found to to defective, the costly terminals are, as a practical matter, irretrievably fixed therein and are thus usually discarded with the defective header.
The second common prior art technique also beings with molding plastic headers. However, the terminals are not molded in place, rather, oversized openings are formed during molding and the terminals are later inserted therein. The excess space in the openings is filled with a material which both seals the openings and firmly fixes the terminals in place. For example, an epoxy material can be used. This method was an improvement over the aforementioned method in that the loss of higher cost metallic terminals was reduced. However, it did not provide a complete solution to the problem because the manufacturing process was more costly as it was substantially complicated and lengthened due to the requirement of additional material and steps.
It is, therefore, a principal object of this invention to provide an improved insulative header assembly with metallic lead through terminals therein; also, to provide a method for the manufacture of the header which overcomes the stated problems of the prior art.